1. Field of the Invention
The present invention relates to an optical sheet and a method for producing the optical sheet and, more particularly, to an optical sheet used for photoelectrical devices and the method for manufacturing it.
2. Description of Related Art
Currently, conventional optical sheets (prism sheets) are widely used in many kinds of photoelectrical devices (e.g. the backlight module of a LCD device). Generally speaking, conventional optical sheets (prism sheets) are made by injection molding process. In most cases, a pretreatment for the mold for manufacturing the conventional optical sheets (prism sheets) before injection molding is required. These pre-treatments include forming grooves on a surface of a mold for transferring-printing and forming the corresponding prisms of the conventional optical sheets (prism sheets). However, the formation of grooves (e.g. V-cut processing or etching) on the surface of a mold is complicate and takes a very long time. On the other hand, the grooves on the surface of the mold for transferring-printing and forming the corresponding prisms of the conventional optical sheets are easily worn after frequent transferring-printing through injection molding. Therefore, the lifetime of the mold used for transferring-printing pattern of prisms of the conventional optical sheets (prism sheets) is not long. Hence, the cost for maintaining, developing or modifying the mold for the conventional optical sheets (prism sheets) is high.
Therefore, it is desirable to provide an improved method to mitigate and/or obviate the aforementioned problems.
The object of the present invention is to provide a method for manufacturing optical sheets to reduce the cost for mass-producing the optical sheets and save the time for mass-producing the optical sheets.
Another object of the present invention is to provide a method for manufacturing optical sheets to extend the lifetime of the mold used for producing the optical sheets.
Another object of the present invention is to provide an optical sheet to simplify the adjusting or the switching of the patterns of the lens or the prisms of the optical sheet.
Another object of the present invention is to provide an optical sheet with a smooth surface.
To achieve the object, the method for manufacturing a lens-implanted optical sheet of the present invention includes following steps: (A) laying a patterned screen mask having a plurality of holes or grooves on an inner surface of a mold; (B) coating or transferring-printing a layer of an adhesive or a binder on part of said inner surface through said grooves or said holes of said patterned screen mask; (C) removing said patterned mask from said inner surface of said mold; (D) spraying or distributing a plurality of lens or prisms and locating said lens or said prisms on said adhesive or said binder on said inner surface of said mold; closing said mold and injecting a polymer into said mold to form a molded optical sheet; and (F) opening said mold and taking out said molded optical sheet.
Another method for manufacturing a lens-implanted optical sheet of the present invention includes following steps: (A) coating or transferring-printing a layer of an adhesive or a binder on part of an inner surface of a mold; (B) laying a plurality of lens or prisms on said inner surface of said mold through the binding of said adhesive or said binder; (C) closing said mold and injecting a polymer into said mold to form a molded optical sheet; and (D) opening said mold and taking out said molded optical sheet.
The lens-implanted optical sheet of the present invention includes: a base plate; and a plurality of lens or prisms embedded in said base plate.
Other objects, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.